How much swapcache can help (with graphs)

I love graphs. Jan Lentfer made some! Both of these show recent speed improvements in DragonFly – especially some spectacular results from swapcache(8) and the recent NCQ tagging improvements. (Note that only the third graph represents the NCQ improvements; the first two graphs were done before.)

The first one is a comparison of pgbench running on the same hardware twice – once with the 2.8 release of DragonFly, and once with a recent 2.9 version. 2.9 is definitely looking to be faster than 2.8.

Next up is a 2.9 system run with and without swapcache, showing an astounding difference between the two. It’s pretty clear just how much performance improvement you can get from swapcache… (see Jan’s notes on the setup after the graphic.)